1. Field of the Invention
The present invention relates to luminaires for use in lighting extensive areas such as may be found along highways and which may be used for area lighting such as parking lots and the like. It relates more particularly to the servicing of such luminaires and especially to efficient arrangements permitting rapid removal and installation of critical components of such luminaires.
2. Description of the Prior Art
Luminaires used for outdoor lighting frequently employ mercury vapor and sodium vapor lamps which provide high-intensity light. Typical installations, in the past, have involved the placement of the luminaires on long arms extending from the tops of high poles near the areas to be illuminated. Along highway rights-of-way, for example, long lines of posts close to the roadway have been necessary with mast arms extending over the roadway. Such lines of posts with long mast arms located close to, or extending over, the edges of the road are not generally considered to be esthetically attractive and are recognized to present a definite hazard of collision for any vehicles which go out of control and off the road. Damage to posts and luminaires located close to highways is a cause of serious losses every day.
To overcome the disadvantages of long mast arms and closely spaced poles, a new reflector and a new refractor have been provided which, when mounted together with a lamp in a suitable housing, produce intense twin beams of light providing a rectangular area of illumination more uniform than has heretofore been commercially feasible with such lamps. This development enables superior illumination over a long and substantially rectangular area of increased size from lamps of a given size which are located farther from the area than hitherto. However, this capability to illuminate a larger and rectangular area from a greater distance carries with it requirements relating to arrangements of reflectors and refractors and particularly to their manner of assembly on the upper ends of straight posts which make it difficult to service the luminaires.